Composite steel plate



J. A. HUNTER. TTTTTTTTTTTTTTTTTT E.

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. JZ I UNTTRD STATES FFICE.

JOI-IN A. HUNTER, OF PHILADELPHIA, PENNSYLVANIA.

COMPOSITE VSTEEL PLATE.

SPECIFICATION forming part of Letters Patent No. 537,463, dated April 16, 1895.

Application led November 13, 1893. Serial No( 490,787. (No model.)

To @ZZ whom it may concern.:

Be it known that I, JOHN A. HUNTER, a citizen of the United States, residing in Philadelphia, Pennsylvania, have invented certain Improvements in Composite Steel Plates, cbc., of which the following is a specification.

The object of my invention is to prepare slabs or plates having a hard resisting surface, and a softer and more yielding backing, an object which I attain in the manner hereinafter set forth, reference being had to the accompanying drawings, in which the three figures represent successive stages in the preparation of a plate in accordance with my invention.

Figure l isa sectional view of the plate at the end of the first stage; Fig. 2, a similar View at the end of the second stage, and Fig. 3, a similar view at the end at the third and last stage.

In carrying out my invention I first produce, by casting or otherwise, a soft steel plate and then, While the the same is highly heated, cast upon the face of the same alayer of iron, which is afterward subjected to any of the usual processes whereby partial decarbonization of the same is effected forthe purpose of convertingit into steel capable of being hardened and tempered, and is finally tempered throughout the Whole or a part of its mass. By this means I am enabled to produce a plate havinga surface of any desired degree of hardness and a back of softer metal the two being rmly united,'for it has been found in practice that by casting the mass of iron upon the face of a body of highly heated steel, an intimate union of the two bodies is effected and a homogeneous block or plate is produced.

In carrying out my invention abody of steel A may be first run into the bottom of a mold, and the body of cast iron B may then be poured in directly upon the top of this mass of steel, the greater specific gravity of the latter being relied upon to prevent the disturbance of the same by the pouring of the iron on top of it, although it will be preferable to permit the steel to partially cool before pouring the iron into the mold, the steel, however, still retaining a high degree of heat when the iron is brought into contact with it, or a steel plate,

slab or block produced in any available manner Vmay be iirst highly heated and then introduced into the mold in order. to provide a base upon which to pour the mass of cast iron.

"When the composite block such as shown in Fig. 1 has become cold, or sufficiently cool to permit handling, the cast iron portion of the blockis subjected to any of the ordinary convertingopcrations whereby partial decarbonization of the iron can be effected and the same reduced to a condition for being hardened and tempered, the composite plate at this stage being represented in Fig. 2, where the converted portion of the plate is represented atB. For carrying out this part of the process I may resort to the treatment set forth in my Patent No. 498,062, dated May 23, 1893, or `the iron portion of the composite plate may be subjected to any of the usual cementation processes and may be afterward hardened or tempered in any ordinary manner throughout either the whole or a part of its mass, as shown in Fig. 3, where the hardened ortempered portion of the plate is represented at B2, the mass of steel forming the backing for the mass of iron being protected from injury or change during such converting, hardening and tempering operations, so that it preserves its original character and provides a backing for the hardened or tempered face of the plate. Myinvention is of special advantage in the manufatnre of armor plates or armor piercing projectiles, lthe latter having an outer surface of hardened steel and an interior core or heart of soft steel.

Having thus described my invention, I claim and desire to secure by Letters Patent-T- The mode herein described of producing plates, blocks, or other articles having a hardened steel face, with a soft steel backing, said mode consisting in casting a mass of iron upon a backing of steel, converting said cast iron mass into steel capable of being hardened or tempered, and then hardening or tempering the same, substantially as specified.

In testimony whereof I have signed my name to this specication in the presence of two subscribing Witnesses.

JNO. A. HUNTER.

Titnessesz WILLIAM A. BARR, JosErH H'. KLEIN.

Sio 

